Kevin DeSchwazi said:
the input iron is 1:10 Cinemag,
This is not accurate information. As far as I know, API has NEVER used Cinemag input iron in any of their pres, and most of the old iron was more like 1:7 or 1:8 steel core. While you probably will get a decent sound w/ Cinemag, there are a ton of other options out there like Sowter, Lundahl, etc... Jensen and Reichenbach 115K-E transformers have been used by API in the past, and are still available new. They've also used their own input iron, which, I believe was the 2622, but that's no longer available new.
Don't expect to get any use out of the actual PCB itself. The pin outs will be different, you'll have to remove most or all of the existing parts, and it will probably be a pain to mount. Good luck getting the DOA out without overheating it, be careful! In reality, it will probably be way easier to start from scratch on a perf board or fab a new board.
You'll need to tie the secondaries of the output tranny in serial, and this transformer won't give you the 3rd set of outputs for a meter, but, who cares anyways, use your DAW or tape meters.
The power supply is an easy build, but you can buy a Power-One (or any other brand) +/-16V supply and expect good results wth the 312 circuit. You'll have to add some regs or something to get 48VDC if you want phantom. You'll also need a pad if you expect to pump drums or loud GTR's through this thang, but that could easily be added on a DPDT switch or relay. I'd consider adding a polarity switch too.
It's a simple circuit, and a good first project. Good luck...
...the 2520's are cool..kinda slow and vintage sounding....if you socket the opamp you can drop John Hardy 990c's (clean!) or Fred Forssell's (also clean but different) opamps in for different flavors although you will need to adjust the power supply (by simply turning the screw on a pot) since 2520's run at +/- 18 volts and the other guys run at +/- 24 (amazing headroom)...keep us updated...
